The first novel, and consequentially the first season, is by far the best self contained story in the series. Ned really grounds the narrative except for a few trips to Essos with Dany who has her own tight, focused story with great side characters. Stark vs Lannisters + King's Landing being a backstabbing shithole city keeps things moving, and rather simple.
Book 2 is where the GRRM really starts stepping out of his comfort zone and introducing tons new characters, conflicts, and locations. I totally get where a tv viewer could come from seeing it not live up to the first season, especially because not enough time is given to any of the scenes except a few select setpieces to let you learn the new characters and their motivations.
Lucky for you guys, the third book, and most likely the next seasons, really makes everything in the second pay off a thousand times over. Its fucking crazy, to put it mildly. Really one of the most entertaining books I've read, with more twists, suspense, insane levels of badassedness, and small but poignant character moments than any TV show or something like that I can think of.
In fact, book 3 is so good, they decided one season can't do it justice, so they are splitting it in two. I am really looking forward to seeing some of this shit on TV.
After book 3?